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Analog Devices Inc. LT1676IS8#TRPBF
- Part No.:
- LT1676IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1676IS8#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 550MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:10,032
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Product details
Overview
LT1676IS8#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode synchronous step-down switching regulator IC designed for high-efficiency DC/DC conversion in automotive and telecom systems. It operates from 7.4V to 60V input, delivers up to 700mA peak switch current, features fixed 100kHz switching frequency with 250kHz synchronization capability, and maintains stable regulation under light-load conditions without pulse skipping - enabling use in IEEE 1394 and cellular battery charger accessories.
For engineers reviewing the LT1676IS8#TRPBF datasheet, LT1676IS8#TRPBF pinout, LT1676IS8#TRPBF application, or LT1676IS8#TRPBF equivalent, key selection criteria include its true current-mode control architecture, adaptive dV/dt switch drive, 1.24V reference accuracy, shutdown quiescent current of 30µA, and SO-8 package thermal resistance of 110°C/W - all critical for high-voltage industrial power supply design.
Technical Context
The LT1676IS8#TRPBF implements true current-mode control using an internal transconductance error amplifier (400–1000 µmho) and a dedicated current comparator referenced to the VC pin voltage. Its dual-dV/dt output switch architecture dynamically adjusts slew rate based on load: high dV/dt mode (1.6 V/ns) engages above 1.35V VC for efficiency at medium-to-heavy loads; low dV/dt mode (0.2 V/ns) activates below threshold to improve light-load controllability and eliminate pulse skipping.
It integrates oscillator, bias regulation, and protection circuitry in a monolithic die. The VCC pin powers internal control logic from the output rail (not VIN), reducing input supply current draw; shutdown is controlled via SHDN pin with 0.2–0.8V threshold and lockout hysteresis (1.245V/1.260V); SYNC pin accepts 130–250kHz external clocks with 1.5–2.2V amplitude requirement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.4V to 60V - supports direct connection to 48V telecom rails and automotive battery systems with cold-crank tolerance. |
| Switch Current Limit | 0.55A to 0.70A (typical 0.7A) - sets maximum deliverable output current before cycle-by-cycle current limiting engages. |
| Reference Voltage | 1.240V ±15mV - defines feedback setpoint accuracy; enables precise 3.3V, 5V, or custom output regulation via resistor divider. |
| Switching Frequency | 100kHz (±10kHz) - balances EMI performance and magnetics size; synchronizable to 130–250kHz for noise avoidance. |
| Shutdown Current | 30µA (typical) - enables ultra-low-power standby in battery-backed systems such as cellular accessory chargers. |
| Thermal Resistance θJA | 110°C/W (SO-8 package) - determines maximum power dissipation before junction temperature exceeds 125°C under PCB copper constraints. |
| Feedback Bias Current | 600–1500nA - limits minimum FB divider impedance to ≤10kΩ for reliable short-circuit protection and reference accuracy. |
Pinout & Package
LT1676IS8#TRPBF is housed in an 8-pin plastic SOIC (SO-8) package with standard JEDEC MS-012AC footprint, rated for –40°C to +125°C operating junction temperature and 110°C/W thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SHDN (Pin 1) | Shutdown control input | Pulled below 0.3V to enter 30µA shutdown; hysteresis between 1.245V (off) and 1.260V (on) enables user-defined UVLO extension above 6.7V. |
| VCC (Pin 2) | Internal bias supply input | Connected to regulated output to reduce VIN current draw; powers control circuitry after startup, improving overall efficiency. |
| VSW (Pin 3) | Switch emitter node | High-dV/dt switching node (up to 10V/ns); requires short traces and ground plane isolation to minimize EMI and coupling into FB/VC pins. |
| GND (Pin 4) | Analog and power ground reference | Reference for feedback amplifier and internal reference; must be star-connected near FB divider to avoid ground bounce errors. |
| VIN (Pin 5) | Main high-voltage input supply | Accepts 7.4–60V; supplies output switch and startup bias; requires low-ESR, high-ripple-current input capacitor. |
| SYNC (Pin 6) | External clock synchronization input | Logic-compatible input accepting 130–250kHz signals; automatically disabled during FB-induced oscillator slowdown for short-circuit safety. |
| FB (Pin 7) | Inverting input of error amplifier | Compares output voltage (via resistor divider) to 1.24V internal reference; low voltage triggers oscillator slowdown for short-circuit protection. |
| VC (Pin 8) | Error amplifier output / current comparator input | Loop compensation node; connects to RC network for stability; clamped at ~2V to limit peak switch current. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive dV/dt switch drive | Automatically selects high-slew (1.6 V/ns) or low-slew (0.2 V/ns) mode based on VC voltage - preserves efficiency at full load while ensuring stable regulation down to zero load. |
| True current-mode control | Uses VC pin voltage to directly set peak switch current per cycle - provides inherent line and load transient rejection plus cycle-by-cycle overcurrent protection. |
| VCC-powered bias regulation | Draws control power from output rail instead of VIN after startup - reduces input quiescent current by >90% compared to VIN-powered controllers at high input voltages. |
| FB-triggered oscillator slowdown | Reduces switching frequency linearly from 100kHz to ~25kHz when FB falls below 0.83×VREF - maintains control during short-circuit without requiring external circuitry. |
| Integrated UVLO with programmable lockout | Combines internal 6.7V UVLO with SHDN pin hysteresis - allows designer to raise effective input undervoltage threshold using external resistor divider. |
Applications
| Automotive DC/DC Converters | Telecom 48V Step-Down Converters |
|---|---|
Use Scenario: Converting 9–16V automotive battery (up to 60V during load dump) to stable 3.3V or 5V for infotainment ECUs and ADAS sensors. IC Role / Device Role / Timing Role: Primary step-down controller managing high-voltage transients, providing current-mode loop stability, and enabling safe shutdown during ignition-off. Use Value: 60V absolute max rating and 7.4V min operating voltage ensure operation across cold-crank, run, and load-dump conditions without external protection. | Use Scenario: Regulating -48V or +48V telecom distribution bus to 5V/3.3V for line cards and optical modules. IC Role / Device Role / Timing Role: High-efficiency buck controller delivering up to 700mA with minimal board area using SO-8 package and 100kHz frequency. Use Value: 100kHz fixed frequency simplifies EMI filter design; synchronization capability avoids beat frequencies in multi-rail systems. |
| Cellular Phone Battery Charger Accessories | IEEE 1394 Step-Down Converters |
Use Scenario: Powering USB-C PD adapters or wireless charging base stations requiring wide-input compatibility with wall adapters (9–24V) and automotive inputs. IC Role / Device Role / Timing Role: Primary DC/DC stage converting variable adapter output to constant 5V/9V/12V for downstream USB-PD negotiation circuits. Use Value: 30µA shutdown current extends standby battery life; adaptive dV/dt eliminates audible noise and improves light-load efficiency. | Use Scenario: Generating 3.3V from 12V or 24V FireWire (IEEE 1394) bus power for digital audio/video interface ICs. IC Role / Device Role / Timing Role: Compact, low-noise buck regulator meeting strict jitter and EMI requirements of high-speed serial data links. Use Value: SO-8 package and 100kHz operation minimize layout area and radiated emissions - critical for signal integrity in mixed-signal applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | Higher 75V input rating, 1.2A switch current, but fixed 2MHz frequency and no SYNC capability. | Better suited for space-constrained designs needing higher current; lacks adjustable shutdown threshold and oscillator slowdown. | Select LTC3631EMSE#PBF when >700mA output and smaller magnetics are required; avoid if 48V telecom short-circuit protection or programmable UVLO is critical. |
| LM5164QDDARQ1 | Automotive-grade (AEC-Q100), 100V input, 500mA switch current, integrated high-side MOSFET, but requires external bootstrap capacitor. | Designed for automotive front-end supplies; includes enhanced fault reporting and spread-spectrum EMI reduction. | Select LM5164QDDARQ1 for ASIL-B compliant systems; avoid if SO-8 footprint compatibility or VCC-powered bias efficiency is mandatory. |
Compared with LTC3631EMSE#PBF and LM5164QDDARQ1, the LT1676IS8#TRPBF uniquely combines 60V input capability, adaptive dV/dt control, FB-triggered oscillator slowdown, and VCC-powered bias in a legacy SO-8 package - making it optimal for cost-sensitive, thermally constrained 48V telecom and industrial converter upgrades where pin compatibility and proven reliability matter.
Availability
LT1676IS8#TRPBF is available at Aetrix Electronics and suitable for automotive DC/DC converters, telecom 48V step-down converters, and IEEE 1394 power supplies requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1676IS8#TRPBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear products including the LT1676 series.
The LT1676 product line was designed specifically for high-input-voltage, high-efficiency buck conversion in harsh environments - targeting automotive, industrial, and telecom infrastructure where wide VIN range, robust short-circuit protection, and minimal external components are essential.
FAQ
What is the maximum input voltage rating for the LT1676IS8#TRPBF?
The LT1676IS8#TRPBF has an absolute maximum input voltage rating of 60V on the VIN pin, with guaranteed operation from 7.4V to 60V. This allows direct interfacing with 48V telecom systems and automotive battery rails including load-dump transients. Exceeding 60V risks permanent damage to the internal switch and control circuitry, regardless of duration.
Does the LT1676IS8#TRPBF require an external freewheeling diode?
Yes, the LT1676IS8#TRPBF requires an external Schottky diode connected between VSW and GND. It does not integrate a synchronous rectifier. A Schottky diode such as MBR160 (60V, 1A) is recommended to minimize forward voltage drop and eliminate reverse recovery losses - critical for achieving >90% efficiency at 48V-to-5V conversion.
How does the LT1676IS8#TRPBF handle short-circuit conditions?
The LT1676IS8#TRPBF handles short-circuits via two coordinated mechanisms: first, its current-mode control limits peak switch current to ~700mA; second, when FB voltage drops below ~0.83×VREF, the oscillator frequency slows linearly from 100kHz to ~25kHz - increasing minimum off-time to maintain control and prevent current runaway. This dual protection requires no external components.
Can the LT1676IS8#TRPBF operate with zero output load?
Yes, the LT1676IS8#TRPBF can operate stably with zero external load due to its adaptive dV/dt switch drive. When VC falls below 1.35V, it enters low-dV/dt mode, relaxing minimum on-time requirements and eliminating pulse skipping behavior. The device's own VCC bias current (~4mA) provides sufficient internal load to sustain regulation without instability.
What is the purpose of the VCC pin on the LT1676IS8#TRPBF?
The VCC pin on the LT1676IS8#TRPBF powers the internal control circuitry from the regulated output rail rather than VIN. This reduces total input supply current - especially critical at high VIN - improving overall efficiency. During startup, the part draws bias from VIN until VOUT reaches ~2.9V, then seamlessly transitions to VCC powering. A 0.1µF bypass capacitor is recommended if VOUT is >1 inch from VCC.
LT1676IS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7.4V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 51V
- Current - Output:
- 550mA (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1676IS8#TRPBF FAQ
1.How can I place an order for LT1676IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1676IS8#TRPBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT1676IS8#TRPBF reliable?
The price and inventory of LT1676IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1676IS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1676IS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1676IS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1676IS8#TRPBF?
LT1676IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1676IS8#TRPBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT1676IS8#TRPBF?
For technical support, including LT1676IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1676IS8#TRPBF requirements.
6.How does Aetrix verify that LT1676IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1676IS8#TRPBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT1676IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1676IS8#TRPBF?
All LT1676IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1676IS8#TRPBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT1676IS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1676IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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